1. Field of the Invention
The present invention relates to packet data transmission between a base station controller (BSC) and a base transceiver station (BTS) for a code division multiple access (CDMA) system such as cellular mobile telephone system, personal communication service (PCS) and wireless local loop (WLL) system and, more particularly, to a trunk routing device and method for a CDMA system which automatically assigns and establishes a trunk path for sending packet data between the BSC and the BTS using a trunk router.
2. Description of the Related Art
Generally, the CDMA system has E1/T1 type trunks connecting the BSC and the BTS and includes a plurality of paths for sending a packet between the BSC and the BTS.
As the individual trunks are connected to nodes in a one-to-one basis, the BSC or BTS has to assign paths available among numerous transfer paths for every packet in order to establish a path for sending the packet between the BSC and the BTS. That is, the BSC or BTS is needed to add a desired trunk ID to a specific field to assign and establish a packet transfer path for every packet. Thus the packet is transferred only via trunk paths.
In such a system, the BSC or BTS uses statistical values measured for the utilization status or utilization ratio of the trunks between them in assigning and establishing a trunk path for sending a packet, thus relying on the statistic values and causing a bias of the packet transfer path. This results in overload on a specific trunk path.
Also, the system is required to have the nodes unnecessarily as many as the trunks, because the individual trunks are connected to the nodes in a one-to-one basis.
Furthermore, there are some cases where all packets using the corresponding trunks are missing while replacing a trunk cable between the BSC and the BTS.
It is, therefore, an object of the present invention to provide a trunk routing device and method for a CDMA system, which is contrived to implement a trunk router that automatically assigns and establishes a trunk path for sending a packet between the BSC and the BTS, i.e., automatically performing a routing between one node and a plurality of trunks in the unit of packet, with a consequence of sequential and uniform routing of all transfer paths and thereby enhancing the efficiency of the transfer paths.
It is another object of the present invention to provide a trunk routing device and method for a CDMA system, which is contrived to have a trunk router for performing a routing between one node and a plurality of trunks in the unit of packet, thus reducing the number of required nodes.
Specifically, the ultimate objective of the present invention is to provide a trunk routing device and method for a CDMA system designed to store information about trunk connection between the BSC and the BTS and the initial position of a router switch at the current path, detect a base station ID of the designation address from a packet received from the BSC via one node, and sequentially switching the position of the router switch at the current path to the trunk connected to the base station ID for sending the packet, thus uniformly utilizing all transfer paths connected to the designation address of the packet to increase the utility efficiency of trunks and, during replacement of a trunk cable, causing a loss of only one packet without affecting the entire transmission of packet data.
To achieve the above object of the present invention, there is provided a trunk routing device for a CDMA system, which assigns and establishes a path for sending a packet via a trunk between a base station controller and a base transceiver station, the trunk routing device including: a router transmit block for storing information about trunk connection between the base station controller and the base transceiver station and information about the initial position of a current router switch, and sequentially switching packets, received from one node connected to the base station controller, to the respective trunks linked to the destinations of the individual packets in the unit of packet; and a router receive block for sequentially multiplying the packets received from the base transceiver station via the trunks and sending the multiplied packets to the node.
In another aspect of the present invention, there is provided a trunk routing method, which is to send a packet received from a base station controller to a base transceiver station via a plurality of trunks, the trunk routing method including the steps of: storing information about trunk connection between the base station controller and the base transceiver station and information about the initial packet transfer path position, for initialization; receiving a new packet from one node connected to the base station controller and detecting a destination address from the packet; and sequentially checking a plurality of trunks at the current position of a router switch, switching the position of the router switch to the next trunk connected to the detected destination address, and sending the packet to the base transceiver station via the trunk.
In further another aspect of the present invention, there is provided a trunk routing method, which is to send a packet received from a base transceiver station to a base station controller via a plurality of trunks, the trunk routing method including the steps of: sequentially checking the status of the respective FIFO""s connected to the respective trunks for buffering the packet received from the base transceiver station via the trunks; and sequentially reading out the packet from the respective FIFO""s in the unit of packet while the respective FIFO""s are empty, according to the result of the checking step, multiplying the packet and sending the multiplied packet to a node connected to the base station controller.